Fromm Family Foods, based in Mequon, Wisconsin, and Champion PetFoods, headquartered in Edmonton, Alberta, released statements last month saying they were severing ties with Chewy and continuing their commitments to independent pet food distributors.

The moves followed a decision in April by Tuffy’s Pet Foods Inc. to pull its products from Chewy. Tuffy’s makes NutriSource, PureVita and Natural Planet.

Fromm Family Foods makes a wide variety of food for dogs and cats branded under the Fromm Family name. On its Facebook page, the company posted a statement saying, “Fromm believes our products are best sold by retailers who know our product and can offer pet parents what’s right for their specific dog or cat. As a result of Chewy’s sale to PetSmart, they are no longer an authorized retailer of Fromm Products.”

In a letter to customers on its website, Champion PetFoods said it was pulling its brands ORIJEN and ACANA from Chewy. “Like many of you, we are disappointed in Chewy’s decision to sell their business,” the letter said. “The ownership change means they no longer meet our definition of pet specialty.”

Representatives from Fromm and Chewy did not respond to interview requests on Wednesday. Through a spokeswoman, PetSmart said it had no comment.

Reached by phone Wednesday afternoon, Michelle Granger, Champion’s director of marketing, said the company believes it’s inevitable that Chewy’s business model will change. “When small stores or small chains are bought up by larger ones, the focus does shift,” she said. “Typically in our industry, the focus becomes more about volume than the needs of pet lovers.”

Specialty stores, Granger said, “are better set up to educate customers on what makes our product special.” But she said Chewy “did a great job” with education and personal service. “We wouldn’t have been in that store if we didn’t think they did a great job.”

Founded in South Florida in 2011 by millennial entrepreneurs who met in a computer chat room, Chewy rapidly grew by offering a wide array of products at competitive prices and low shipping rates. It endeared itself to customers with personalized service, including surprising them with hand-painted portraits of their pets.

After Chewy and PetSmart announced the acquisition in April, a deal said to be worth more than $3 billion, longtime customers worried that Chewy would lose what made it special.

The subject continues to be discussed on Chewy’s Facebook page, with some customers noting changes in prices and disappearance of the severed brands, and others saying they haven’t noticed major changes.

Just like before the acquisition, customers post photos of their cats sitting inside Chewy shipping boxes, and words of thanks for the surprise portraits of their pets.

Several Fromm and Champion customers reacted with frustration to the announcements on the companies’ Facebook pages.

Some Champion customers said they would miss Chewy’s low costs and complained that specialty brick and mortar stores require long commutes, charge more for the company’s products, and noted that many specialty online retailers also charge more for shipping.

One said Chewy operates the same now as before the acquisition and questioned why the company no longer meets Champion’s definition of specialty.

Champion responded by posting, “Mass retailers operate different business models than specialty stores. To be successful in mass retail stores, brands need to invest significantly in advertising. We choose to invest in our foods instead.”

Granger acknowledged “a lot of pet lovers were disappointed by the decision.” But she said many were unaware of the acquisition. Once informed, “most support the decision.”

Mark Kalaygian, publishing director and editor in chief of PetBusiness.com, a trade industry website, wrote in a recent blog entry that more companies are likely to follow suit by pulling its brands from Chewy, and that the moves have been well received by independent pet stores across the country.

“For years now, Chewy.com has been a particular focus of ire for many independent retailers because of what has been perceived as its predatory pricing practices,” he wrote. “In fact, many in the pet industry say that overwhelming pricing pressure is exactly what eventually drove PetSmart to acquire the online pet food seller.”

The pullouts are also a show of support by the specialty brands to independent retailers, said Debbie Phillips-Donaldson, editor in chief of PetfoodIndustry.com, a trade website.

Small stores that were decimated by the rise of big box pet stores fought back, in part, by working with small independent brands that pledged not to sell in the chains, she said in a phone interview.

Then the small stores were stung when some of those specialty brands were absorbed by large companies, and their new owners broke those pledges, she said.

Ben Gomes-Casseres, a professor at Brandeis International Business School and an expert on mergers and e-commerce, said in an interview that he was puzzled by the pet food makers’ decisions to sever ties with Chewy.

The three producers “might have certain values they want to promote, and that’s their decision,” Gomes-Casseres said. But he questioned whether it makes good business sense to withdraw from such a lucrative sales channel such as Chewy.

“It’s [comparable] to the bookstore business,” he said. “I love independent bookstores but at the same time I love Amazon, too. I have no problem buying from Amazon if I know I’m getting the quality I’m looking for.”

Gomes-Casseres said such producers “have to be careful not to cut off their nose to spite their face. That’s a risk always when you make a decision to change marketing channels.”